The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
Diesel engines may be operated in a conventional combustion mode and a Premixed Compression Ignition (PCI) combustion mode. PCI is an advanced diesel combustion technique that may reduce diesel engine emissions. With PCI, fuel is injected into the combustion chamber of the cylinder much earlier in the combustion stroke than would be done for conventional diesel combustion. The desired fuel amount is supplied significantly before the piston reaches the compression top dead center (TDC). The early injected fuel is mixed sufficiently with the air before the piston reaches the compression TDC. Thus, the technique provides a lean and well mixed state of air/fuel mixture before ignition.
A diesel engine may be switched from a conventional combustion mode to PCI combustion mode during low-load operating conditions. Therefore, engine load conditions may be monitored to ensure that the combustion mode is switched to PCI combustion mode at low load conditions. However, switching to PCI combustion mode even at low engine load conditions may result in high NOx emissions without appropriate combustion gas conditions.
Further areas of applicability will become apparent from the description provided herein. It should be understood that the description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.